Enhanced braking system and method

ABSTRACT

Certain exemplary embodiments can provide for automatic power control and/or torque boost for retarding a machine that considers a machine weight and/or a machine slope. The automatic power control and/or torque boost can provide a control margin under retard. Certain exemplary embodiments can control, or attempt to control, a speed of the machine at less than a maximum safe speed.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to, and incorporates by referenceherein in its entirety, pending U.S. Provisional Patent Application Ser.No. 60/493,215 filed 7 Aug. 2003.

BACKGROUND

For a machine comprising at least one electric motor, a retard torqueand/or power can be used to slow motion of the machine. Slowing themachine can depend upon a plurality of factors such as machine weight, aslope of a path of the machine, and/or the available retard torqueand/or power. Often, machines can be operated with a retard torqueand/or power control that does not allow a sufficient control margin incertain situations.

U.S. Pat. No. 6,299,263 (Uematsu), which is incorporated by referenceherein in its entirety, allegedly recites an “automatic retardercontroller for a vehicle, which can prevent overheating, and can moreprecisely control the vehicle speed to remain constant. For thispurpose, in the automatic retarder controller which is mounted on aload-carrying vehicle together with a cooled retarder (31) for exertinga braking force in response to a driving signal, and which automaticallycontrols the driving signal so that the slope descending speed of thevehicle remains nearly constant, a detector for detecting the loadingweight of the vehicle is included, and the controller impresses the gaincorresponding to the detected loading weight upon the driving signalwhile the controller controls the vehicle speed to remain constant.” SeeAbstract.

U.S. Pat. No. 6,249,733 (Smith), which is incorporated by referenceherein in its entirety, allegedly recites an “automatic control foroperating an engine retarder, service brakes, and an automatictransmission associated with earth moving equipment is provided. Theautomatic control monitors engine speed and responsively producescontrol signals to maintain engine speed within predetermined limit.”See Abstract.

U.S. Pat. No. 6,150,780 (Young), which is incorporated by referenceherein in its entirety, allegedly recites torque “is distributed bycalculating first and second torque commands using a requested torqueand a ratio of speeds of first and second wheels and limiting them inaccordance with respective torque command approved ranges and approvedchange rates; converting the limited torque commands to horsepowercommands and limiting them in accordance with respective horsepowercommand approved ranges and approved change rates; and converting thelimited horsepower commands to present torque commands. Maximumhorsepower available is determined by using an engine speed to determinea nominal amount of available horsepower; applying a desired load statussignal and an actual engine load status signal to aproportional-integral A regulator; and using the nominal amount ofavailable horsepower and an output signal of the regulator to determinethe maximum amount of available horsepower. Thermal protection isprovided by obtaining component temperatures of a plurality ofcomponents; normalizing each component temperature; obtaining anormalized drive system temperature by determining a maximum value ofthe normalized component temperatures; and comparing the normalizeddrive system temperature with at least one predetermined maximumnormalized temperature and using a result of the comparison to determinewhether a corrective action is needed. A truck is started on an inclineby determining whether its speed is below a predetermined speed limit, aservice brake is applied, and an accelerator pedal is depressed, and, ifso, permitting a propulsion torque to build without requiring anoperator override action.” See Abstract.

SUMMARY

Certain exemplary embodiments can provide for automatic power controland torque boost for retarding a machine that considers a machine weightand a machine slope. The automatic power control and torque boost canprovide a control margin under retard. Certain exemplary embodiments cancontrol, or attempt to control, a speed of the machine at less than amaximum safe speed.

Certain exemplary embodiments comprise a method comprising: for amachine comprising a wheel drive system comprising a braking system,comparing an acceleration to a predetermined acceleration threshold;determining a dynamic maximum retard torque associated with the brakingsystem based on said comparing activity; controlling a retard torque tono greater than the dynamic maximum retard torque; and affecting aretard power. Certain exemplary embodiments comprise a methodcomprising: for a machine comprising a wheel drive system and a brakingsystem, obtaining information indicative of an inclination of themachine with respect to a travel direction of the machine; obtaining anestimated weight related to the machine; and based on the informationindicative of an inclination of the machine with respect to a traveldirection of the machine of the machine and the estimated weight relatedto the machine, controlling a retard torque related to the wheel drivesystem to no greater than a dynamic maximum retard torque.

BRIEF DESCRIPTION OF THE DRAWINGS

A wide variety of potential embodiments will be more readily understoodthrough the following detailed description, with reference to theaccompanying drawings in which:

FIG. 1 is a block diagram of an exemplary embodiment of an automaticpower control and torque boost system 1000;

FIG. 2 is a diagram of an exemplary set of torque/speed curves 2000.

FIG. 3 is a flow diagram of an exemplary embodiment of an automaticpower control and torque boost method 3000; and

FIG. 4 is a block diagram of an exemplary embodiment of an informationdevice 4000.

DEFINITIONS

When the following terms are used herein, the accompanying definitionsapply:

-   -   acceleration—a time rate of change in the speed (linear and/or        angular) of an entity.    -   alternating current—an electric current that reverses direction        in a circuit at regular intervals.    -   boost power—a power level associated with retarding a wheel        drive system that is above a rated power of at least one        electric braking system component. Boost power can be provided        temporarily for retarding the wheel drive system.    -   controller—a device and/or set of machine-readable instructions        for performing one or more predetermined tasks. A controller can        comprise any one or a combination of hardware, firmware, and/or        software. A controller can utilize mechanical, pneumatic,        hydraulic, electrical, magnetic, optical, informational,        chemical, and/or biological principles, signals, and/or inputs        to perform the task(s). In certain embodiments, a controller can        act upon information by manipulating, analyzing, modifying,        converting, transmitting the information for use by an        executable procedure and/or an information device, and/or        routing the information to an output device. A controller can be        a central processing unit, a local controller, a remote        controller; parallel controllers, and/or distributed        controllers, etc. The controller can be a general-purpose        microcontroller, such the Pentium IV series of microprocessor        manufactured by the Intel Corporation of Santa Clara, Calif. In        another embodiment, the controller can be an Application        Specific Integrated Circuit (ASIC) or a Field Programmable Gate        Array (FPGA) that has been designed to implement in its hardware        and/or firmware at least a part of an embodiment disclosed        herein.    -   control range—an extent within which an operating parameter can        be adjusted.    -   determine—ascertain.    -   determinator—a device adapted to determine a value.    -   drive—a means by which power is transmitted to the wheels of a        vehicle.    -   dynamic—changeable.    -   electrical properties—characteristics of a device and/or system        adaptable to use electricity. Electrical properties can relate        to a quality and/or quantity of electrical power safely        handleable by the device and/or system.    -   electric motor braking system—a plurality of components adapted        to retard, or attempt to retard, motion of an electric motor.    -   electric motor—a motor powered by electricity. An electric motor        can comprise two members, one stationary, called the stator, and        the other rotating, called the rotor. Either member can utilize        one or more magnets, electromagnets, and/or ferromagnetic        components.    -   expected—predicted.    -   fail-safe processor—a processor adapted to determine a maximum        safe velocity of a machine.    -   feedback metric—a value output by a system that is used as one        of a plurality of inputs to some portion of that system.    -   Global Positioning System (GPS)—a system adaptable to determine        a terrestrial location of a device receiving signals from        multiple satellites.    -   Geographic Information System (GIS)—an information management        system tied to geographic data. For example, a GIS can comprise        various types of geographical-data sets, such as topography,        elevation, buildings, hydrology, road networks, urban mapping,        land cover, zoning, and/or demographic data, etc. Data sets in a        GIS can be tied together geographically to provide a spatial        context.    -   gross weight processor—a processor adapted to estimate a weight        of a machine.    -   incline—a slope with respect to a horizontal plane.    -   incline processor—a processor adapted to receive information        indicative of an inclination of the machine with respect to a        travel direction of the machine.    -   inclinometer—an instrument for indicating the inclination of a        vehicle.    -   increase—to become greater or more in size, quantity, number,        degree, value, intensity, and/or power, etc.    -   information—data.    -   input—a signal, data, and/or information provided to a device        and/or system.    -   input processor—a processor adapted to receive information        related to at least one wheel drive, the information can        comprise a speed, a torque, and/or a power, etc.    -   instructions—directions adapted to perform a particular        operation or function.    -   level—a relative position on a scale.    -   limit—a finite extent.    -   limited range—a finite extent of values.    -   load metric—a value that describes a maximum allowable amount of        energy impartable to an electrical and/or mechanical component        of a vehicle.    -   machine—a device and/or vehicle adapted to perform at least one        task.    -   maximum—a greatest extent.    -   measurement—a value of a variable, the value determined by        manual and/or automatic observation.    -   metric—a measurement.    -   metric processor—a processor adapted to calculate at least one        load metric related to a rotational speed and a torque        associated with a motor.    -   mine haul truck—a motor vehicle adapted to transport bulk        materials.    -   motion—movement due to rotation and/or translation.    -   motor—something that converts electricity to linear and/or        angular motion.    -   predetermined—established in advance.    -   predetermined limit—an extent established in advance.    -   predetermined acceleration threshold—a limit on a time rate of        change in velocity, the limit established in advance.    -   predetermined period of time—a time interval established in        advance.    -   predetermined retard power limit—an expected amount of power        safely handleable by an electrical braking system under retard.        The predetermined retard power limit can be related to        electrical properties of a motor and/or the electric braking        system.    -   predetermined threshold—a limit established in advance.    -   processor—a hardware, firmware, and/or software machine and/or        virtual machine comprising a set of machine-readable        instructions adaptable to perform a specific task. A processor        acts upon information by manipulating, analyzing, modifying,        converting, transmitting the information to another processor or        an information device, and/or routing the information to an        output device.    -   rate—a quantity measured with respect to another quantity.    -   rated capacity—an expected capability. For example, an electric        motor can have an ability to transfer an expected amount of        mechanical energy related to an amount of electrical energy        provided to the electric motor.    -   rating—an expected capability.    -   render—make perceptible to a human, for example as data,        commands, text, graphics, audio, video, animation, and/or        hyperlinks, etc., such as via any visual and/or audio means,        such as via a display, a monitor, electric paper, an ocular        implant, a speaker, a cochlear implant, etc.    -   retard—to attempt to slow; to resist motion.    -   retard envelope—a predetermined allowable range of torque values        related to electrical properties of an electric braking system.    -   retard metric—a value related to a maximum safe velocity, a        predetermined limit, and/or a speed metric.    -   retard power—electrical power associated with applying a torque        in a direction opposite to a direction of travel.    -   retard processor—a processor adapted to determine a retard power        based on a rotational speed and a torque related to a motor.    -   retard setpoint—a threshold indicative of a desired velocity,        deceleration, and/or deceleration rate of the machine. The        retard setpoint can be provided by an operator, such as by the        operator pressing downward on a retard pedal in a cab of a mine        haul truck.    -   retard torque—a moment of a force applied to slow an object's        rotation and/or linear motion in a predetermined direction. Also        equivalent to the product of an angular retard deceleration and        a mass moment of inertia of an object.    -   retard torque setpoint—a threshold indicative of a desired        retarding torque or deceleration of the machine. The retard        setpoint can be provided by an operator, such as by the operator        pressing downward on a retard pedal in a cab of a mine haul        truck, or by a controller.    -   retard power setpoint—a threshold indicative of a desired        retarding power of the machine provided by a controller.    -   retard torque—a moment of a force applied in a direction        opposite to a direction of an object's motion. Also equivalent        to the product of an angular retard deceleration and a mass        moment of inertia of an object.    -   safe—relatively free from risk or danger. A machine can be safe        when controllable as to velocity.    -   speed—a distance traveled during a predetermined time interval.        A speed can be translational or rotational in nature.    -   speed metric—a value related to a rotational speed and/or a        torque of a motor associated with a vehicle.    -   tachometer—an instrument used to measure the rotational speed of        a rotating shaft.    -   temporarily—existing and/or occurring for a limited period of        time.    -   torque—a moment of force acting upon an object; a measure of the        force's tendency to produce torsion and rotation in the object        about an axis equal to the vector product of the radius vector        from the axis of rotation to the point of application of the        force and the force vector. Equivalent to the product of angular        acceleration and mass moment of inertia of the object.    -   torque boost processor—a processor adapted to increase a maximum        turning force.    -   torque range processor—a processor adapted to determine an        extent of turning forces.    -   translational—along a linear and/or curvilinear path;        non-rotational;    -   truck—a motorized machine designed for carrying or pulling a        primarily non-human load.    -   user interface—any device for rendering information to a user        and/or requesting information from the user. A user interface        includes at least one of textual, graphical, audio, video,        animation, and/or haptic elements.    -   value—an assigned or calculated numerical quantity.    -   vehicle—a device or structure for transporting persons or        things. A vehicle can be a car, truck, locomotive, and/or mine        haul. truck, etc.    -   velocity—a translational speed.    -   weight—a force with which a body is attracted to Earth or        another celestial body, equal to the product of the object's        mass and the acceleration of gravity.    -   wheel—a solid disk or a rigid circular ring connected to a hub        and designed to turn around an axle.    -   wheel drive system—a plurality of components by which power is        transmitted from an energy source, such as a fossil-fuel powered        internal combustion engine, to the wheels of a machine. A wheel        drive system can comprise, for example, an engine; a generator        and/or alternator; an electric motor; a speed sensor; a torque        sensor; a plurality of mechanical power transmission components,        such as a clutch, torque converter, transmission, driveshaft,        differential, and/or gearbox, etc.; a system controller; an        inverter; a variable frequency motor controller; an electrical        braking system adapted to generate power from the machine as it        retards; and/or an electrical energy dissipation circuit        associated with the electrical braking system; etc.    -   wireless—any means to transmit a signal that does not require        the use of a wire or guide connecting a transmitter and a        receiver, such as radio waves, electromagnetic signals at any        frequency, lasers, microwaves, etc., but excluding purely visual        signaling, such as semaphore, smoke signals, sign language, etc.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of an exemplary embodiment of an automaticpower control and torque boost system 1000, which can comprise a machine1050.

Machine 1050 can be, for example, a car, truck, locomotive, and/or haultruck, etc. In certain exemplary embodiments, machine 1050 can comprisea wheel drive system 1125, which can be a single wheel drive systemdriving a plurality of wheels of the machine. In certain exemplaryembodiments, wheel drive system 1125 can be one of a plurality of wheeldrive systems driving a plurality of wheels of the machine.

Wheel drive system 1125 can comprise a motor 1150, which can be analternating current electric motor and/or a direct current electricmotor. Motor 1150 can have performance characteristics such as arelationship between a rotational speed and a torque, such as theangular speed and torque of a rotor and/or output shaft of the motor. Acurve can be plotted for motor 1150 relating rotational speed to torque.The velocity of machine 1050 can be controlled via controlling a torqueassociated with motor 1150. Applying a retarding torque and/or power viamotor 1150 can provide an opposing torque and/or power to a velocityand/or direction of travel of machine 1050. Applying a retarding torqueto machine 1050 can control and/or attempt to be control the velocity ofmachine 1050, particularly when machine 1050 traverses a downward grade.

A shaft associated with motor 1150 can be coupled to a speed sensor1200, which can be adapted to provide a rotational frequency and/orangular speed of the shaft. Speed sensor 1200 can be adapted to directlyor indirectly measure an actual rotational speed of motor 1150. Speedsensor 1200 can be coupled to motor 1050 mechanically,electro-mechanically, magnetically, and/or optically, etc. For example,a direct contact speed sensor 1200 can sense signals from magneticbrushes to provide a measurement of rotational speed. As anotherexample, an indirect contact speed sensor 1200 can sense an opticalsignal reflected off of a surface to provide a measurement of rotationalspeed. Speed sensor 1200 can detect, measure, and/or transmit a speedmeasurement related to motor 1150 to a processor, such as a powercomparator 1450 and/or an acceleration comparator 1500. The rotationalspeed associated with motor 1150 can be proportional to a power appliedto hold and/or move machine 1050. In certain exemplary embodiments,speed sensor 1200 can measure a rotational speed of a component of wheeldrive system 1125 that is driven by motor 1150, and/or a translational(e.g., linear, curvilinear, etc.) speed of machine 1050.

The translation speed of machine 1050 represents a rate of change inposition of machine 1050 in a direction of travel relative to areference point over a predetermined time interval. The translationspeed can be reported in, for example, feet per second, kilometers perhour, and/or miles per hour, etc. The rotational speed of a component ofwheel drive system 1125 can be a rate at which the component rotates ina predetermined time and/or an angular speed of the componentrepresenting a rate of change in a rotational position of the shaftrelative to a reference point over a predetermined period of time. Therotational speed can be reported in, for example, revolutions persecond, revolutions per minute, revolutions per hour, degrees persecond, degrees per minute, radians per second, and/or radians perminute, etc. The translation speed associated with a linear and/orcurvilinear motion of machine 1050 can be converted to the rotationalspeed and vice versa.

System 1000 can comprise a torque sensor 1250, which can measure atorque related to motor 1150. For example, torque sensor 1250 canmeasure torque utilizing a strain gauge, an angular accelerometer, adynamometer, and/or by measuring an electrical property such as atwo-phase current transformation in conjunction with a two-phase fluxtransformation to calculate instantaneous torque, frequency, slip-speed,and/or phase shift, etc. Torque sensor 1250 can detect, measure, and/ortransmit information indicative of a torque related to motor 1150 to aprocessor, such as power comparator 1450. The torque associated withmotor 1150 can be considered as proportional to a force applied to holdand/or move machine 1050. The torque associated with motor 1150 can beproportional to the power applied to hold and/or move machine 1050. Incertain exemplary embodiments, torque sensor 1250 can measure a torqueapplied to a component of wheel drive system 1125 that is driven bymotor 1150, and/or a translation (e.g., linear) force of machine 1050.

An inclinometer 1300 can be comprised by and/or in machine 1050 and/orsystem 1000. Inclinometer 1300 can be adapted to measure an angle ofincline associated with machine 1050. Inclinometer 1300 can provideinformation indicative of machine 1050 traversing a gradient such as adownhill gradient. Inclinometer 1300 can measure a slope via a devicebased on an accelerometer, capacitance, electrolysis, gas bubble inliquid, mercury, and/or pendulum, etc. Accelerometers can measure,display, and/or analyze acceleration and vibration associated with agradient related to machine 1050. Capacitive tilt sensors can takenon-contact measurements of tilt and inclination of machine 1050.Electrolytic tilt sensors can produce pitch and roll measurementsrelated to machine 1050. A gas bubble in liquid can be comprised of asight glass filled with liquid adapted to measure an incline associatedwith machine 1050. A mercury type tilt sensor can comprise a small metalor glass can, inside of which are two electrodes and a minute drop ofmercury adapted to measure an incline associated with machine 1050. Apendulum type sensor can comprise a pendulum or weight in conjunctionwith a rotary sensor adapted to measure an incline associated withmachine 1050. In certain exemplary embodiments, an inclinometer, such asa laser-based optical inclinometer, can be positioned outside machine1050 to determine the incline of machine 1050 and/or any portionthereof.

In certain exemplary embodiments, inclinometer 1300 can be adapted towirelessly obtain information related to the incline of machine 1050.For example, inclinometer 1300 can obtain information indicative oflocation from a GPS-based device and/or a GIS device, etc. Inclinometer1300 can obtain information indicative of terrain slopes from anengineering entity, the USGS, and/or a commercial surveying entity, etc.Inclinometer 1300 can be communicatively coupled to a safe speedprocessor 1650. Information measured, obtained, and/or determined usinginclinometer 1300 can be wirelessly transmitted to at least onetransceiver.

A weight sensor 1350 can be comprised by and/or in machine 1050 and/orsystem 1000. Weight sensor 1350 can be adapted to detect a weightrelated to machine 1050. Weight sensor 1350 can be a strain gauge, loadcell, nuclear based weight sensor, and/or electrical sensor detecting aparameter related to weight, etc. Weight sensor 1350 can becommunicatively coupled to safe speed processor 1650. In certainexemplary embodiments, a weight sensor 1350, such as a traditionalscale, can be positioned outside machine 1050 to determine the weight ofmachine 1050 and/or any portion thereof. In certain exemplaryembodiments, weight sensor 1350 can be adapted to wirelessly obtaininformation related to the weight of machine 1050. Information measured,obtained, and/or determined using weight sensor 1350 can be wirelesslytransmitted to at least one transceiver.

Motor 1150 can be controllable via braking system 1100, which can beadapted to control the retard torque and/or power related to motor 1150responsive to a plurality of inputs and/or conditions. Braking system1100 can comprise power comparator 1450, acceleration comparator 1500, aretard setpoint comparator 1550, a boost processor 1600, safe speedprocessor 1650, a torque controller 1700, and/or a power controller1750.

Power comparator 1450 can calculate an actual power from measurementsprovided by, for example, speed sensor 1200 and torque sensor 1250.Power comparator 1450 can calculate power on a discrete and/or timeaveraged basis. Power comparator 1450 can be adapted to compare theactual power to a rated power associated with braking system 1100. Underretard, the rated power can be related to an ability of a mechanicaland/or electrical component of braking system 1100 to dissipate heatand/or transfer electrical energy without overheating. For example, ifmotor 1150 is an alternating current electric motor, the rated retardpower can be limited by the windings of motor 1150, a component relatedto a speed controller associated with motor 1150, a grid box (e.g. asystem which is used for dissipating power generated by a motor underretard), and/or an electrical wire transmitting power to motor 1150,etc. Power comparator 1450 can be adapted to provide a feedback metricrelated to the actual power and a rated power of at least one wheeldrive to torque controller 1700 and/or power controller 1750.

Acceleration comparator 1500 can be adapted to receive a speedmeasurement from a device such as speed sensor 1200, and/or derive aspeed measurement from a torque measurement provided by a device such astorque sensor 1250. Acceleration comparator 1500 can calculate anacceleration associated with machine 1050, such as an angular and/ortranslational acceleration of machine 1050, via comparing a firsttranslational or rotational speed measured at a first time to a secondtranslational or rotational speed measured at a second time.Acceleration comparator 1500 can be adapted to average accelerations ofa plurality of wheel drives of machine 1050, average accelerationsrelated to machine 1050 over a predetermined time period, and/or comparean acceleration of machine 1050 to a predetermined threshold. Thepredetermined threshold can be, for example, approximately 0.05 m/s, 0.1m/s², 0.123 m/s², 0.2 m/s², 0.211 M/s², 0.43 m/s², 0.576 m/s², and/orany acceleration value above, below, or in between those values.Comparing the acceleration to a predetermined threshold can provide asignal adaptable to adjust a dynamic maximum torque associated withtorque controller 1700 and/or power controller 1750.

Machine 1050 can comprise a retard setpoint sensor 1400. Retard setpointsensor 1400 can be adapted to detect a measurement indicative of aretard setpoint. The retard setpoint can relate to a requested amount ofretard from an operator of machine 1050. The retard setpoint can beproportional to a retard pedal depression by the operator of machine1050. Retard setpoint sensor 1400 can be communicatively coupled toretard setpoint comparator 1550.

Retard setpoint comparator 1550 can be adapted to compare the retardsetpoint associated with retard setpoint sensor 1400 to a predeterminedthreshold. Retard setpoint comparator 1550 can provide a retard setpointmetric to boost processor 1600. For example, if the retard setpointrequests a maximum retarding torque for a predetermined time period, theretard setpoint metric supplied by retard setpoint comparator 1550 canprovide a signal to boost processor 1600 indicative of a request for ahigher dynamic maximum torque.

Electric braking system 1100 can comprise a safe speed processor 1650,which can provide a maximum safe speed and/or a speed metric indicativeof a maximum safe speed to torque controller 1700 and/or powercontroller 1750. Safe speed processor 1650 can be adapted to calculateand/or determine the maximum safe speed responsive to informationobtained from inclinometer 1300 and/or weight sensor 1350. For example,when machine 1050, having a weight sensed by weight sensor 1350,traverses a downhill grade of a slope detected by inclinometer 1300, themaximum-safe speed can represent a speed above which machine 1050 wouldbe, or would be at risk of being, in an uncontrollable condition, suchas when insufficient retard and/or braking power exists to slow themachine to a safe translational speed for a given incline. Safe speedprocessor 1650 can provide the maximum safe speed to torque controller1700 and/or power controller 1750, which can be indicative of a speedbelow which torque controller 1700 and/or power controller 1750 shouldcontrol and/or attempt to control machine 1050. Safe speed processor1650 can provide a signal adapted to render the maximum safe speed on auser interface. The maximum safe speed can be dynamic and change withrespect to load, location, incline, and/or machine weight.

Boost processor 1600 can be adapted to receive information from aplurality of information devices such as acceleration comparator 1500and/or retard setpoint comparator 1550. Responsive to a signalindicative of retard setpoint comparator 1500 requesting a valueincrease in the dynamic maximum torque, and/or signal indicative of acontinued acceleration of machine 1050 above a predetermined rate fromacceleration rate comparator 1500, boost processor 1600 can be adaptedto provide instructions to increase a value of the dynamic maximumretard torque and/or power associated with torque controller 1700 and/orpower controller 1750.

Torque controller 1700 can be adapted to provide a signal to control aretard torque generated by motor 1150. A retard torque generated bymotor 1150 can restrain, and/or or attempt to restrain, an accelerationand/or speed of machine 1050.

Torque controller 1700 can accept input signals, for example, from powercomparator 1450, boost processor 1600, and/or safe speed processor 1650,etc. Torque controller 1700 can be adapted to provide an output signalto a device related to motor 1150. The output signal from torquecontroller 1700 can be based on a proportional, integral, and/orderivative control algorithm in comparing at least one input signal to avalue indicative of a setpoint. Torque controller 1700 can provide theoutput signal responsive to the feedback metric provided by powercomparator 1450, gradient provided by inclinometer 1300, weight providedby weight sensor 1350, actual retard torque provided by torque sensor1250, and/or retard torque limit, etc. A dynamic maximum torque canlimit the signal indicative of the retard torque from torque controller1700. The dynamic maximum torque can be changed responsive to a signalfrom boost processor 1600. The outputs signal can be based, for machine1050, on the gradient, weight, actual retard torque, and/or retardtorque limit, etc.

Power controller 1750 can accept input signals, for example, from torquecontroller 1700, power comparator 1450, boost processor 1600, and/orsafe speed processor 1650, etc. Power controller 1700 can be adapted toprovide an output signal to a device related to motor 1150. The outputsignal from power controller 1700 can be based on a proportional,integral, and/or derivative control algorithm in comparing at least oneinput signal to a value indicative of a setpoint. Applying a retardpower from motor 1150 can restrain, and/or or attempt to restrain, anacceleration and/or speed of machine 1050. Power controller 1700 canprovide the output signal responsive to the feedback metric provided bypower comparator 1450, gradient provided by inclinometer 1300, weightprovided by weight sensor 1350, actual retard torque provided by torquesensor 1250, and/or retard torque limit, etc. A dynamic maximum powercan limit the signal indicative of the retard power from powercontroller 1700. The dynamic maximum power can be changed responsive toa signal from boost processor 1600.

Output signals from torque controller 1700 and/or power controller 1750can be constrained by the dynamic maximum torque and/or power. Undernormal retarding operation, a retarding torque and/or power can beapplied to motor 1050 with the dynamic maximum torque and/or power setat a first dynamic maximum torque and/or power that is less than a ratedmaximum torque and/or power associated with a braking system 1100. Forexample, the first dynamic maximum torque and/or power can be, as apercentage of the rated maximum torque and/or power associated withbraking system 1100, approximately 68, 69.5, 70.25, 80.01, 83.2, 85,87.433, 88, 89.9, or 90.32, etc. or any value above, below, or inbetween these values.

Controlling machine 1050 utilizing a dynamic maximum torque and/or powercan assist in a safe operation of machine 1050. In certain exemplaryembodiments, torque controller 1700 and/or power controller 1750 canprovide a signal to a device related to motor 1150 indicative of aretard torque and/or power below, approaching or equal to the firstdynamic maximum value.

Pursuant to a predetermined set of conditions, a value of the dynamicmaximum torque and/or power can be changed, via boost processor 1600.For example, the second dynamic maximum torque and/or power can behigher and/or lower than the first dynamic maximum torque and/or power.The value of the dynamic maximum torque and/or power can be increasedresponsive to a determination of a need to further retard the motion ofmachine 1050, or decreased responsive to a determination of a lack ofneed to further retard the motion of machine 1050. The second maximumtorque and/or power can be, as a percentage of the rated maximum torqueand/or power associated with braking system 1100, such as approximately95, 96.5, 97.25, 99.09, 99.9, 100, 100.133, 101.88, 102.9, or 103.37,105, etc. percent, or any value above, below, or in between thesevalues.

Responsive to a signal from boost processor 1600, a value of the dynamicmaximum torque and/or power can be increased from the first dynamicmaximum to the second dynamic maximum when the signal approaches and/orreaches the first dynamic maximum, and machine 1050 is stillaccelerating and/or additional retarding is desired. In certainexemplary embodiments, torque controller 1700 and/or power controller1750 can provide a signal to a device related to motor 1150 indicativeof a retard torque and/or power up to, approaching, or approximatelyequal to the second dynamic maximum.

On a short term basis a value of the dynamic maximum torque and/or powercan be boosted to a third maximum torque and/or power. The third maximumtorque and/or power can be above the rated maximum torque and/or powerassociated with braking system 1100. The third maximum torque and/orpower can be, as a percentage of the rated maximum torque and/or powerassociated with braking system 1100, approximately 110, 111.5, 113.25,114.09, 114.9, 115, 117.133, 118.88, 119.9, or 120.37, etc. percent, orany value above, below, or in between these values. The third dynamicmaximum torque and/or power can be used as the dynamic maximum torquefor a predetermined period of time. The predetermined period of time inseconds can be, for example, 1, 2.344, 3.1, 7.68, 8, 9.254, 15, 20.225,31, 45.901, and/or 60.13, etc., seconds, and/or any value above, below,or in between these values.

Responsive to a signal from boost processor 1600, a value of the dynamicmaximum torque and/or power can be increased to the third dynamicmaximum when the signal approaches and/or reaches the second dynamicmaximum, and machine 1050 is still accelerating and/or additionalretarding is desired. On a short term basis, torque controller 1700and/or power controller 1750 can provide a signal to motor 1150indicative of a dynamic maximum retard torque and/or power up to thethird dynamic maximum.

The rotational speed of motor 1150 and/or velocity of machine 1050corresponding to a dynamic maximum torque and/or power can depend on agross machine weight (measurable utilizing weight sensor 1350) and/or anincline of a grade being traversed by the machine (measurable utilizinginclinometer 1300). Torque controller 1700 and/or power controller 1750can limit the angular and/or translational speed of machine 1050. In apower region of a retard curve associated with motor 1150, the retardpedal position, the retard torque, and the retard power can all beproportional.

FIG. 2 is a diagram of an exemplary set of torque/speed curves 2000.Certain exemplary embodiments comprise dynamic maximum torque and/orpower levels as described in Table 1:

TABLE 1 Dynamic Maximum Retard Torque and/or Power DescriptionExplanation  88% First Dynamic Continuous retard Maximum Torque withsafety limit 100% Second Dynamic Increased limit to provide MaximumTorque additional retarding torque and/or power for steep grades and/orheavy loads 115% Third Dynamic Short-term assist in recovery MaximumTorque from an over speed condition

Exemplary values of the dynamic maximum retard torque and/or powerlimits, expressed as a percentage of rated retard torque and/or power,as indicated in Table 1 can provide margins for control during retard. Avalue of the dynamic maximum retard torque and/or power limit for normaloperation can be set to approximately 88% of a rated retard power as thefirst dynamic maximum retard torque. The torque/speed curve associatedwith the first dynamic maximum retard torque as a value of dynamicmaximum torque from Table 1 can be graphically illustrated as curve2100. The power/speed curve associated with the first dynamic maximumretard torque as a value of dynamic maximum torque from Table 1 can begraphically illustrated as curve 2150. The torque/speed curve associatedwith the second dynamic maximum retard torque as a value for the dynamicmaximum torque from Table 1 can be graphically illustrated as curve2200. The power/speed curve associated with the second dynamic maximumretard torque as a value for the dynamic maximum torque from Table 1 canbe graphically illustrated as curve 2250. The torque/speed curveassociated with the third dynamic maximum retard torque as a value ofthe dynamic maximum torque from Table 1 can be graphically illustratedas curve 2300. The power/speed curve associated with the third dynamicmaximum retard torque as a value of the dynamic maximum torque fromTable 1 can be graphically illustrated as curve 2350.

For example, consider a truck with two traction motors and a weight ofapproximately one million pounds comprising a wheel drive with a retardsystem with a 3500 kilowatt power limit. If the truck descends aten-percent grade with a rolling resistance of two percent at 19 milesper hour, approximately 3100 kilowatts of retard power are required tomaintain the velocity of the truck and to avoid acceleration. Operatingat about 3100 kilowatts corresponds to a torque approximating the firstdynamic maximum retard torque value for the dynamic maximum retardtorque of 88% of the retard power limit of 3500 kilowatts. In certainexemplary embodiments, additional retarding torque can be available toslow the truck responsive to a predetermined set of conditions. Certainexemplary embodiments can be adapted to maintain the velocity of thetruck within a predetermined velocity range during minor variations ingrade.

In certain exemplary embodiments, when the truck is operating at aretard torque below the first dynamic maximum retard torque value andthe retard pedal input is less than a predetermined threshold, the truckmay accelerate without an applied retard torque (e.g., to reach thedesired/rated downhill velocity). An exemplary situation A on FIG. 2illustrates this condition. Situations such as situation A can compriseany of a plurality of conditions that can reflect any of manycombinations of gross truck-weight; incline, traction, path curvature,and/or velocity of the machine and/or motor, machine and/or drivetraininertia, retard pedal position, propel pedal position, etc. Situation Acan be any set of conditions resulting in a speed/torque and speed/powerrelationship in a particular speed/torque/power state space.

When the retard pedal input exceeds a predetermined threshold indicativeof an operator attempting to slow the truck, the retard torque can beincreased accordingly. The grade traversed by the truck can increase orthe velocity of the truck can increase and cause the retard torque toreach the dynamic maximum retard torque limit (88% of the rated retardtorque and/or power in the example above) of curve 2100 and/or curve2150. This can be shown graphically as situation B on FIG. 2.

As needed, the value of the dynamic maximum retard torque can beautomatically increased above 3100 kilowatts up to the second dynamicmaximum torque and/or power (100% of the rated retard torque and/orpower in this embodiment), illustrated as curve 2200 and/or curve 2250.The value of the dynamic maximum retard torque and/or power limit canremain elevated at the second dynamic maximum until the actual torquelevel once again approaches and/or reaches 88% of the rated retardtorque. Increasing the retarding torque can slow and/or attempt to slowthe truck down. Thus, the torque and rotational speed associated with amotor associated with the truck can traverse, for example, to situationC on FIG. 2 responsive to increasing the value of the dynamic maximumtorque limit.

In certain exemplary embodiments, the dynamic retard torque limitdefined by curve 2200, and the dynamic retard power limit defined bycurve 2250, can be reached as illustrated by situation D on FIG. 2. Achange from situation C to situation D can be indicative of the truckvelocity not sufficiently decreasing despite a torque and/or powerincrease up to the continuous duty maximum level.

To accommodate such scenarios in certain exemplary embodiments, thevalue of the dynamic maximum retard torque and/or power limit can betemporarily boosted to the third dynamic maximum (approximately 115% ofthe rated retard torque in this embodiment), graphically shown as torquecurve 2300 and power curve 2350. The third dynamic maximum (boostfunction) can be activated when the retard pedal is fully activated, thetruck is accelerating, and/or the boost function has not been appliedfor a predetermined period of time, etc.

The value of the dynamic maximum retard torque can be limited by theshort-term electrical carrying capacity of a grid box associated with anelectric motor associated with the truck braking system. The timeinterval for applying the third dynamic maximum retard torque and/orpower can be set to a maximum time interval, such as 20 seconds, and/oruntil the retard torque and/or power is less than the first dynamicmaximum (88% of the rated retard torque in this embodiment) asillustrated by curve 2100.

A warning indicator can prompt an operator of the truck when the valueof the dynamic maximum retard torque is increased. In the example above,the additional 15% retard torque can increase the safe operatingvelocity for the truck to 24 mph. In certain exemplary embodiments, therotational speed and torque of the motor associated with the truck canreach, for example, situation E on FIG. 2. Traversing from situation Dto situation E can be indicative of an increase in torque.

In certain exemplary embodiments, the rotational speed, torque, and/orpower associated with a motor associated with the truck can result insituation F, which can be indicative of a condition where the truckvelocity cannot be controlled by the retard system. Situation Fillustrates a situation where the truck will continue to gain velocityabsent some other force, such as an emergency friction based brakingsystem, decrease in inclination, and/or collision of the truck, etc.

In certain exemplary embodiments, the value of the dynamic maximumretard torque and/or power can be reduced back to the first dynamicmaximum retard torque and/or power level as the torque approaches and/orreaches the first dynamic maximum retard torque and/or power level.

FIG. 3 is a flow diagram of an exemplary embodiment of an automaticpower control and torque boost method 3000, which can be associated witha machine comprising a wheel drive system and a wheel drive brakingsystem. At activity 3100, a rotational speed related to a motorassociated with the wheel drive system can be measured directly,calculated, and/or determined. The rotational speed related to the motorcan be used to determine a power associated with the motor.

At activity 3200, a torque related to a motor associated with the wheeldrive system can be measured directly, calculated, and/or determined.The torque related to the motor can be used to determine a powerassociated with the motor.

At activity 3300, the acceleration of the motor associated with thewheel drive system can be determined by, for example, comparingrotational speeds associated with the motor and/or wheel drive atdifferent times.

At activity 3325, a weight related to the machine can be determined. Theweight related to the machine can be a gross weight of the machine, aweight of any portion thereof, and/or a net weight of a load held by themachine, etc. In certain exemplary embodiments, the weight related tothe machine can be measured utilizing a sensor and/or measurementassociated with the machine. In certain exemplary embodiments, theweight can be detected by a sensor and/or measurement external to themachine and communicated wirelessly to the machine.

At activity 3350, an incline related to the machine can be determined.The incline related to the machine can be an incline of the entiremachine, and/or an incline of any portion thereof, etc. In certainexemplary embodiments, the incline related to the machine can bemeasured utilizing a sensor and/or measurement associated with themachine. In certain exemplary embodiments, the incline can be detectedby a sensor and/or measurement external to the machine and communicatedwirelessly to the machine.

At activity 3400, a retard power can be determined, for example, via acalculation based upon the rotational speed and torque related to themotor. The retard power can be used to determine and/or calculate afeedback metric usable in controlling the motor.

At activity 3450, a maximum safe velocity of the machine can bedetermined. For example, the maximum safe velocity of the machine can bedetermined based on the weight of the machine and/or the incline of themachine. The maximum safe velocity can represent a velocity above whichthe machine would be, or would be at risk of being, in an uncontrollablecondition, such as when insufficient retard and/or braking power existsto slow the machine to a safe velocity for a given downhill incline. Themaximum safe velocity can be dynamic in nature and can change withrespect to load, location, incline, and/or machine weight, etc. Incertain exemplary embodiments, the maximum safe velocity can be renderedvia a user interface. The user interface can be viewable, for example,by an operator of the machine, supervisor of an operator of the machine,dispatcher associated with the machine, manager of the machine, and/orany other person responsible for a safe operation of the machine, etc.

At activity 3500, a predetermined retard power limit can be obtainedand/or determined. For example, the retard power or torque limit can beobtained from electrical system calculations used in designing themachine. The retard power or torque limit can be associated with abraking system capacity. The braking system capacity can be related to amechanical and/or an electrical property of the braking system. Forexample, for a drive comprising an electric motor, the retard power ortorque limit can be related to motor winding size, electrical wiringsupplying power to the motor, grid box design, and/or power dissipationlimitations in a variable frequency drive, etc.

At activity 3600, a feedback metric can be determined. The feedbackmetric can be determined based upon at least one actual power and/ortorque associated with the motor and/or the maximum safe velocity of themachine. The actual power and/or torque can be calculated from the motorrotational speed and/or the torque related to the motor. In certainexemplary embodiments, the feedback metric can be determined responsiveto a comparison between the actual power and/or torque and thepredetermined retard power and/or torque limit associated with themachine. In certain exemplary embodiments, the feedback metric can bedetermined responsive to a comparison between the maximum safe velocityof the machine can be compared to an actual velocity of the machine.

At activity 3650, a retard setpoint can be received from, for example, afoot pedal position provided by an operator of the machine. In certainexemplary embodiments, the retard setpoint can be provided automaticallyresponsive to a machine weight and a slope being traversed by themachine.

At activity 3700, a dynamic maximum retard torque and/or power can beobtained. The dynamic maximum retard torque and/or power can beobtained, responsive to a control algorithm related to the machine. Thecontrol algorithm can comprise operating under normal conditions at afirst dynamic maximum retard torque and/or power, which is at a levelbelow the retard torque and/or power limit.

At activity 3800, the dynamic maximum retard torque and/or power can beincreased. The control algorithm can comprise increasing the dynamicmaximum retard torque and/or power to a second dynamic maximum retardtorque and/or power. The second dynamic maximum retard torque and/orpower can be at a level that is approximately equal to the retard torqueand/or power limit. Increasing the dynamic maximum retard torque and/orpower can be responsive to at least one pre-determined condition. The atleast one predetermined condition can comprise detecting a continuedacceleration while retarding up to the first dynamic maximum retardtorque and/or power, a maximum retard setpoint, and/or exceeding amaximum safe velocity, etc.

At activity 3850, the dynamic maximum retard torque and/or power can betemporarily boosted. The dynamic maximum retard torque and/or power canbe temporarily increased to a third dynamic maximum retard torque and/orpower, which can be above the retard torque and/or power limitassociated with the machine's braking system. The third dynamic maximumretard torque and/or power can be applied for a predetermined timeperiod. Boosting the dynamic maximum retard torque and/or power can beresponsive to at least one pre-determined condition. The at least onepredetermined condition can comprise detecting a continued accelerationwhile retarding up to the second dynamic maximum retard torque and/orpower, a maximum retard setpoint, exceeding a maximum safe velocity,and/or a time elapsed since a previous change in the dynamic maximumretard torque and/or power.

At activity 3900, the retard torque can be controlled. The retard torquecan be controlled responsive to a torque controller output. The torquecontroller output can be determined responsive to the feedback metric,the retard setpoint, an incline of the machine, a weight associated withthe machine, the maximum safe velocity, and/or the dynamic maximumretard torque, etc.

At activity 3950 the retard power can be controlled. In certainexemplary embodiments, the retard power can be controlled indirectly viacontrolling the retard torque. In certain exemplary embodiments, theretard power can be controlled responsive to a power controller output.The power controller output can be determined responsive to the retardcontroller output, the feedback metric, the retard setpoint, an inclineof the machine, a weight associated with the machine, the maximum safevelocity, and/or the dynamic maximum retard torque, etc.

FIG. 4 is a block diagram of an exemplary embodiment of an informationdevice 4000, which in certain operative embodiments can comprise, forexample, power comparator 1450, acceleration comparator 1500, retardsetpoint comparator 1550, boost processor 1600, safe speed processor1650, torque controller 1700, and/or power controller 1750 of FIG. 1.Information device 4000 can comprise any of numerous well-knowncomponents, such as for example, one or more network interfaces 4100,one or more processors 4200, one or more memories 4300 containinginstructions 4400, one or more input/output (I/O) devices 4500, and/orone or more user interfaces 4600 coupled to I/O device 4500, etc.

In certain exemplary embodiments, via one or more user interfaces 4600,such as a graphical user interface, a user can view a rendering ofinformation related to providing automatic power control, fail safespeed control, and/or a torque boost.

Still other embodiments will become readily apparent to those skilled inthis art from reading the above-recited detailed description anddrawings of certain exemplary embodiments. It should be understood thatnumerous variations, modifications, and additional embodiments arepossible, and accordingly, all such variations, modifications, andembodiments are to be regarded as being within the spirit and scope ofthe appended claims. For example, regardless of the content of anyportion (e.g., title, field, background, summary, abstract, drawingfigure, etc.) of this application, unless clearly specified to thecontrary, there is no requirement for the inclusion in any claim of theapplication of any particular described or illustrated activity orelement, any particular sequence of such activities, or any particularinterrelationship of such elements. Moreover, any activity can berepeated, any activity can be performed by multiple entities, and/or anyelement can be duplicated. Further, any activity or element can beexcluded, the sequence of activities can vary, and/or theinterrelationship of elements can vary. Accordingly, the descriptionsand drawings are to be regarded as illustrative in nature, and not asrestrictive. Moreover, when any number or range is described herein,unless clearly stated otherwise, that number or range is approximate.When any range is described herein, unless clearly stated otherwise,that range includes all values therein and all subranges therein. Anyinformation in any material (e.g., a United States patent, United Statespatent application, book, article, etc.) that has been incorporated byreference herein, is only incorporated by reference to the extent thatno conflict exists between such information and the other statements anddrawings set forth herein. In the event of such conflict, including aconflict that would render a claim invalid, then any such conflictinginformation in such incorporated by reference material is specificallynot incorporated by reference herein.

1. A method comprising a plurality of activities, comprising: for amachine comprising a wheel drive system comprising an electric motor andan electric motor braking system, obtaining information indicative of aninclination of the machine with respect to a travel direction of themachine; obtaining an estimated weight related to the machine; based onthe information indicative of the inclination of the machine withrespect to a travel direction of the machine of the machine and theestimated weight related to the machine, controlling a retard torque ofthe electric motor to no greater than a dynamic maximum retard torque;affecting a retard power of the electric motor.
 2. The method of claim1, further comprising: determining a dynamic maximum safe speed for themachine based on the inclination of the machine with respect to a traveldirection of the machine and the estimated weight related to themachine.
 3. The method of claim 1, further comprising: rendering adynamic maximum safe speed via a user interface, the dynamic maximumsafe speed determined based on the inclination of the machine withrespect to a travel direction of the machine and the estimated weightrelated to the machine.
 4. The method of claim 1, further comprising:measuring a speed of the machine.
 5. The method of claim 1, wherein saidcontrolling activity is also based on a difference between a speed ofthe machine and a dynamic maximum safe speed of the machine.
 6. Themethod of claim 1, further comprising: receiving a measurement of theretard torque of the electric motor.
 7. The method of claim 1, furthercomprising: receiving a measurement of a speed of the electric motor. 8.The method of claim 1, wherein said controlling activity is also basedon a retard power related to a speed and the retard torque of theelectric motor.
 9. The method of claim 1, further comprising: receivinga predetermined retard power limit related to the electric motor. 10.The method of claim 1, wherein said controlling activity is also basedon a predetermined retard power limit related to the electric motor. 11.The method of claim 1, wherein the machine comprises an inclinometeradapted to provide the information indicative of the inclination of themachine with respect to the travel direction of the machine.
 12. Themethod of claim 1, further comprising: wirelessly obtaining informationindicative of the inclination of the machine with respect to the traveldirection of the machine.
 13. The method of claim 1, further comprising:wirelessly transmitting information indicative of the inclination of themachine with respect to the travel direction of the machine.
 14. Themethod of claim 1, wherein the information indicative of the inclinationof the machine with respect to the travel direction of the machine isobtained responsive to information indicative of a location obtainedfrom a GPS.
 15. The method of claim 1, wherein the informationindicative of the inclination of the machine with respect to the traveldirection of the machine is obtained responsive to informationindicative of a location obtained from a GIS.
 16. The method of claim 1,further comprising: determining the dynamic maximum retard torque basedon a maximum safe speed of the machine.
 17. The method of claim 1,further comprising: determining the dynamic maximum retard torque basedon a difference between an actual speed of the machine and a maximumsafe speed of the machine.
 18. The method of claim 1, furthercomprising: determining the dynamic maximum retard torque based on acomparison of an acceleration rate of the electric motor to apredetermined threshold.
 19. The method of claim 1, wherein the dynamicmaximum retard torque is less than a rated capacity related to anelectric braking system.
 20. The method of claim 1, wherein the dynamicmaximum retard torque is approximately equal to a rated capacity relatedto an electric braking system.
 21. The method of claim 1, wherein thedynamic maximum retard torque is above a rated capacity related to anelectric braking system.
 22. The method of claim 1, wherein the machineis a truck.
 23. The method of claim 1, wherein the machine is a minehaul truck.
 24. A system comprising: for a machine comprising a wheeldrive system comprising an electric motor and an electric motor brakingsystem, an incline processor adapted to obtain information indicative ofan inclination of the machine with respect to a travel direction of themachine; a weight processor adapted to obtain an estimated weightrelated to the machine; and based on the information indicative of theinclination of the machine with respect to the travel direction of themachine of the machine and the estimated weight related to the machine,a torque controller adapted to control a retard torque of the electricmotor to no greater than a dynamic maximum retard torque.
 25. Amachine-readable medium comprising stored instructions for: for amachine comprising a wheel drive system comprising an electric motor andan electric motor braking system, obtaining information indicative of aninclination of the machine with respect to a travel direction of themachine; obtaining an estimated weight related to the machine; and basedon the information indicative of the inclination of the machine withrespect to the travel direction of the machine and the estimated weightrelated to the machine, controlling a retard torque of the electricmotor to no greater than a dynamic maximum retard torque.